Submersible pumps are used throughout the world to pump water out of various well configurations. The submersible pump typically has a plurality of impellers which work in series to develop pressure within the pump. The water is expelled from the pump discharge and is therefore pressurized and available for usage. In general, a submersible pump will incorporate a number of impellers, or stages, which may vary in their respective diameters and port openings. Such pumps are commonly referred to as multistage pumps.
Generally, the impellers of each stage of a multistage pump adds pressure to the water entering each stage. Accordingly, as the number of stages in a pump are increased, the pump's total output pressure also increases. A pump will, however, lose efficiency if water is re-circulated within a particular stage. For example, recirculated water diminishes the magnitude of the pressure entering the next stage in the series. In addition, recirculation may also severely decrease pump life if abrasive particles are passed into the pump and dwell in the stage.
What is needed is a multistage submersible pump that incorporates one or more seals on each impeller in order to prevent recirculation. What is further needed is a seal designed to ensure that recirculation within the stage is kept at a minimum and that any debris which may pass through the pump does not continue to recirculate within it. Thus, what is needed is a pump with an efficient sealing system that keeps recirculation to a minimum. There has also been a need for an improved thrust bearing and wear member configuration in centrifugal pumps. Still further, there has been a need for pump seal arrangements which will compensate for axial and lateral movement of the pump impellers due to thrust forces acting thereon.